how different from between professional brethren and professional colleague? do you even use "brethren" in real life?

how can I get through to you? in what kind of situation do you use this sentence? and how different from "how can I reach you?" thank you for your answer.^^

what's the difference between 'improve' and 'enhance'? is 'improve' used in real life more than 'enhance'? I guess 'enhance' has more formal meaning. is that right? thanks to put up with my mumble jumble.

I don't understand these sentences. please explain them to me grammaticaly. it's doubtful that someone like Ronald Laing, whose name is still disdained 22 years after his death, would have broken as much ground were he not arrogant, angry and unconventional. --> what is "break ground" mean in here? and "were he not arrogant, ~~~" ??????? I'm so confused. could you paraphrase the latter two sentences for me? and thank you for your answer.^^

which is more correct? have you had your lunch? have you eaten your lunch? thank you for your answer.^^

너 아프니? - Are you sick? Is this right expression? I mean, can I talk to somebody that seems to be ill like this? When I'm worried about someone's health what shoud I say? I saw movies in which some people used this expression as meaning -crazy or pervert-. So I'm curious.^^

What is that mean by that? What 'by that' mean? and in what kind of situation do you use them? examples in real life please..

This is a sentence in Garfield comic strips. "Would puddy tat wike a bowl of milk?" I don't understand this forever -ㅁ-.Is this some kind of babytalk? If it is please correct the sentence so I can read. thank you.^^*

what does "play at it" mean? and how different from "play with it"?